JPH11112882A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the overflow of a signal electric charge and to prevent the occurrence of a flicker by executing the sampling operation of the signal electric charge from an image element more than once for every reading period in one screen at the time of driving a thinning and reading mode. SOLUTION: A high speed processing is executed by a jump reading mode (thinning and reading mode) at the time of display in a liquid crystal display part where the high speed processing is required except when a still image is recorded or at the time of AE or AF control. An electric charge sampling pulse is always impressed at first on one screen, that is, the electric charge sampling pulse is impressed at first on one screen even when an element shutter is not used. When exposure is started, whole electric charges in a photodiode are discharged to a substrate and exposure is executed from a state where no electric charge is stored at all. Therefore, the electric charge is discharged to the substrate once per one screen concerning the image element of a line 2 where a transfer pulse 2 is not impressed and reading is not executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus having driving / control means for an all-pixel reading mode for reading out pixel signals from all pixels and a thinning-out reading mode for reading out pixel signals from all pixels. In particular, the present invention relates to an imaging apparatus that can easily switch between a driving operation in a thinning-out reading mode and a driving operation in an all-pixels reading mode.

[0002]

2. Description of the Related Art Recently, CCs used in electronic cameras and the like have been developed.
Since the imaging device using the D imaging device has come to be configured with high pixels, except when recording a still image, without reading all pixels, skip pixels and read.
That is, by performing thinning-out reading, high-speed processing is required.
When the F operation is performed, the operation is performed. When such a thinning-out reading mode operation is performed, reading can be performed at a higher speed because all the pixels are not read than in the mode operation of reading all the pixels. Since a large number of frames can be displayed, it can be displayed as a smooth moving image output, instead of a frame-like screen.

[0003]

When the CCD image pickup device is driven in the skipping read mode (thinning-out reading mode), some of the pixel lines are read out and some are not read out. When exposure is repeated many times, the signal charges overflow from the photodiodes constituting the pixels and may be mixed into the transfer path. In addition, the image forming apparatus has a skip reading mode and an all-pixel reading mode, and even when shifting from the skip reading mode to the all-pixel reading mode, if there is a line that is subjected to multiple exposure and overflows in the skip reading mode, all pixels are read out. At the time of transition to the reading mode, the signal charges remaining in the pixels may be mixed depending on the skipping reading mode.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem in an image pickup apparatus having driving / controlling means for a conventional thinning-out reading mode and an all-pixels reading-out mode. An object of the present invention is to provide an imaging apparatus which prevents overflow of signal charges in a read mode, thereby eliminating the need for performing interlaced scanning and causing no flicker. According to a second aspect of the present invention, there is provided an image pickup apparatus capable of preventing signal charges remaining in the thinned-out readout mode from being mixed in the all-pixels readout mode when shifting from the thinned-out readout mode to the all-pixels readout mode. It is intended to provide a device. Further, according to the present invention, it is possible to prevent signal charges remaining in the thinned-out read mode from being mixed in the all-pixel readout mode when shifting from the thinned-out read mode to the all-pixel readout mode, and to prevent leakage to the register. It is an object of the present invention to provide an imaging device capable of simultaneously removing a smear component that enters. According to a fifth aspect of the present invention, there is provided an imaging apparatus capable of reducing power consumption during an operation of extracting a signal charge from a pixel for an element shutter function and reliably performing an operation of extracting a signal charge. With the goal. It is still another object of the present invention to provide an image pickup apparatus in which a signal charge does not overflow into a transfer path even when abnormally strong light is incident, and a good still image without noise is obtained. And

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 comprises a pixel comprising a plurality of photoelectric conversion elements which are two-dimensionally arranged in a horizontal direction and a vertical direction, respectively. A solid-state imaging device having a vertical register that receives signal charges of pixels and transfers the signal charges in the vertical direction, a horizontal register that transfers signal charges of the vertical registers in the horizontal direction, and control means for driving and controlling the solid-state imaging device. A driving function of an all-pixel reading mode, in which the control means transfers a signal charge from all pixels of the solid-state imaging device to a vertical register and reads a pixel signal;
For every m (m is a positive integer of 2 or more) pixels in the vertical direction, n (n
Has a driving function of a thinning-out reading mode in which signal charges are transferred from one or more pixels to the vertical register and pixel signals are read out, and the signal charges are extracted from the pixels and the photoelectric conversion time of the pixels is controlled. In the thinning-out readout mode, the operation of extracting signal charges from the pixels is performed at least once every one screen readout period.

As described above, the operation of extracting the signal charge from the pixel at the time of driving in the thinning-out reading mode is performed at least once every reading period of one screen. Overflow of signal charge from the
Therefore, even if the same pixel is repeatedly read during the thinning-out readout mode, signal charges from pixels that do not perform the readout do not overflow, so that there is no need to perform interlace scanning and no flicker occurs.

According to a second aspect of the present invention, there is provided a pixel comprising a plurality of photoelectric conversion elements arranged two-dimensionally in a horizontal direction and a vertical direction, and a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction. A solid-state imaging device having a horizontal register that transfers signal charges of the vertical register in a horizontal direction; and a control unit that drives and controls the solid-state imaging device, wherein the control unit includes the solid-state imaging device. A driving function in an all-pixel reading mode in which signal charges are transferred from all the pixels of the element to the vertical register and pixel signals are read out, and n (n is 1 or more) for every m (m is a positive integer of 2 or more) pixels in the vertical direction A positive integer of pixels) to transfer signal charges from the pixels to the vertical register and read out pixel signals in a thinning-out readout mode, and extract signal charges from the pixels. An element shutter function for controlling the electric conversion time, and when performing the all-pixel readout mode drive immediately after the thinning-out readout mode drive, the operation of extracting the signal charge from the pixel immediately before the start of the exposure is performed at least once. It is configured to do so.

As described above, when shifting from the thinned-out reading mode to the all-pixels reading mode, the signal charges are extracted one or more times immediately before the start of the exposure in the all-pixels reading mode. Signal charges due to multiple exposure of pixels are discharged and can be prevented from being mixed in when reading out all pixels.

According to a third aspect of the present invention, there is provided a pixel comprising a plurality of photoelectric conversion elements arranged two-dimensionally in a horizontal direction and a vertical direction, and a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction. A solid-state imaging device having a horizontal register that transfers signal charges of the vertical register in a horizontal direction; and a control unit that drives and controls the solid-state imaging device, wherein the control unit includes the solid-state imaging device. A driving function in an all-pixel reading mode in which signal charges are transferred from all the pixels of the element to the vertical register and pixel signals are read out, and n (n is 1 or more) for every m (m is a positive integer of 2 or more) pixels in the vertical direction A positive integer of pixels) to transfer signal charges from the pixels to the vertical register and read out pixel signals in a thinning-out readout mode, and extract signal charges from the pixels. An element shutter function for controlling the electric conversion time, and when performing the all-pixel reading mode driving immediately after the thinning-out reading mode driving, at the beginning of a one-screen reading period immediately before reading pixel signals from all pixels. In addition, the signal charges are transferred from all the pixels to the vertical register.

As described above, when shifting from the thinning-out readout mode to the all-pixels readout mode, the transfer of signal charges from all the pixels to the vertical register is performed at the beginning of the readout period of one screen immediately before the pixel signals of all the pixels are read out. By doing so, the signal charges in all the pixels become empty, and the exposure starts from the empty state, so that the signal charges due to the multiple exposure in the thinning-out reading mode are prevented from being mixed in when reading out all the pixels. .

According to a fourth aspect of the present invention, there is provided a pixel comprising a plurality of photoelectric conversion elements arranged two-dimensionally in a horizontal direction and a vertical direction, and a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction. A solid-state imaging device having a horizontal register that transfers signal charges of the vertical register in a horizontal direction; and a control unit that drives and controls the solid-state imaging device, wherein the control unit includes the solid-state imaging device. A driving function in an all-pixel reading mode in which signal charges are transferred from all the pixels of the element to the vertical register and pixel signals are read out, and n (n is 1 or more) for every m (m is a positive integer of 2 or more) pixels in the vertical direction A positive integer of pixels) to transfer signal charges from the pixels to the vertical register and read out pixel signals in a thinning-out readout mode, and extract signal charges from the pixels. The device has an element shutter function for controlling the electric conversion time. Immediately after reading out the pixel signals of all pixels, immediately after reading out the pixel signals of all pixels, After the transfer of the signal charge, the signal charge in the vertical register is transferred at a high speed.

As described above, when shifting from the thinning-out reading mode to the all-pixel reading mode, the signal charges are transferred from all the pixels to the vertical register immediately before the pixel signals of all the pixels are read out. Becomes empty, and the exposure starts from the empty state,
Signal charges due to multiple exposure in the thinning-out read mode are prevented from being mixed in when reading out all pixels. In addition, by transmitting and discharging the signal charges transferred into the vertical register at a high speed, smear components leaking into the register can be simultaneously generated. It can be removed.

According to a fifth aspect of the present invention, there is provided a pixel comprising a plurality of photoelectric conversion elements arranged two-dimensionally in a horizontal direction and a vertical direction, and a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction. A solid-state imaging device having a horizontal register that transfers signal charges of the vertical register in the horizontal direction, and an imaging device including control means for driving and controlling the solid-state imaging element, wherein the control means An element shutter function for extracting a signal charge and controlling a photoelectric conversion time, wherein the operation of extracting the signal charge from the pixel is performed n times (n is a positive integer of 1 or more) immediately before the start of exposure. It is.

Conventionally, in an image pickup apparatus, an element shutter operation for outputting a moving image (an element shutter is a method of adjusting the amount of accumulated photocharge by variably setting a photocharge accumulation time of a photodiode constituting a pixel). This is a function that has the same effect as opening and closing a mechanical shutter, and eliminates the need for a movable section.) From the beginning of one screen to immediately before the start of an exposure period in one screen. A signal charge sampling pulse is output to perform a signal charge sampling operation. As described above, when the sampling pulse is output from the beginning of one screen to immediately before the start of the exposure period in one screen, power consumption increases. By performing n times immediately before, power consumption can be reduced. In addition, the signal charge is extracted only n times immediately before the start of the exposure, so that the signal charge can be reliably discharged before the start of the exposure. Even if such a removal operation is performed, the charge extraction operation is completed during the exposure period. Since this is a period from the point of time when the accumulated signal charge is transferred to the vertical register, there is no change.

According to a sixth aspect of the present invention, there is provided a pixel comprising a plurality of photoelectric conversion elements arranged two-dimensionally in a horizontal direction and a vertical direction, and a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction. A solid-state imaging device having a horizontal register that transfers signal charges of the vertical register in the horizontal direction, and an imaging device including control means for driving and controlling the solid-state imaging element, wherein the control means In a reading period in which an element shutter function for extracting a signal charge and controlling a photoelectric conversion time and using an output of the solid-state imaging device as a moving image output, the operation of extracting the signal charge from the pixel is performed immediately before the start of exposure, where n (n is In a readout period in which the output of the solid-state imaging device is used as a still image, the operation of extracting signal charges from the pixels is performed only once. Repeating those configured to prohibit performs exposure operation.

In the case where the output of the solid-state imaging device is used as a still image, if there is a period in which the signal charge is extracted from the pixel and a period in which the signal operation is not performed, noise occurs at the time of the switching. Although horizontal streaks occur in the still image, as in the invention according to claim 6,
In the readout period when the output of the solid-state imaging device is used as a still image, the operation of extracting signal charges from the pixels is repeatedly performed to prohibit the exposure operation, thereby preventing horizontal streaks due to noise. In addition, when there is a switching of the signal charge extracting operation, the pulse voltage of the signal charge extracting pulse is high, and at the time of the switching, the power supply voltage greatly changes and horizontal streaks such as a luminance step occur. By continuously performing the operation of extracting the signal charges, the power supply voltage does not fluctuate at the time of outputting a still image, and a good still image output can be obtained.

[0017]

Next, an embodiment will be described. FIG. 1 is a block diagram showing a schematic configuration when an imaging apparatus according to the present invention is applied to an electronic camera. FIG.
Wherein 1 is a C that photoelectrically converts an optical signal into an electrical signal.
Light is input to the CCD image sensor 1 through a lens (not shown) and a diaphragm 2 to the CCD image sensor 1. Reference numeral 3 denotes a correlated double sampling circuit (CDS) for removing noise from the output of the CCD image sensor 1.
An amplifier 4 amplifies the output of the correlated double sampling circuit 3. Reference numeral 5 denotes an A / D converter for converting the output of the amplifier 4 which is analog data into digital data.
This is a process circuit that processes a signal from the D imaging device 1 as video data. Reference numeral 7 denotes a DRAM for temporarily storing video data signal-processed by the process circuit 6,
Reference numeral 8 denotes a compression / decompression circuit for compressing video data stored in the DRAM 7 and decompressing the compressed data.
The compressed data is recorded on the recording medium 9, and the recording medium 9
The recording data read out from is expanded.

An AF 10 controls the focus using video data obtained by processing a signal from the CCD image sensor 1.
A circuit, 11 an AE circuit for controlling exposure, 12 an auto white balance circuit for setting a white balance, and 13 a liquid crystal for displaying video data obtained by processing a signal from the CCD image sensor 1 on a liquid crystal. It is a display unit. Reference numeral 14 denotes an external display interface circuit for displaying video data on an external monitor or the like. 15 is a CCD image sensor 1
A timing generator 16 controls the timing of the above-mentioned operations, a reference numeral 16 denotes an SG circuit for transmitting a synchronization signal to the timing generator 15, and a reference numeral 17 denotes a CPU which controls all the operations of the above-described components.

In the electronic camera having such a configuration,
The electric signal obtained by the photoelectric conversion in the CCD image sensor 1 is correlated double sampling circuit 3, amplifier 4, A /
The signal passes through the D converter 5 and is processed in the process circuit 6 to become a video signal. Then, the first video signal is recorded on the recording medium 9 or displayed on the liquid crystal display unit 13 to adjust the angle of view on what kind of still image is to be recorded. Is recorded.

Next, a first embodiment of a mode of driving and controlling the CCD image pickup device by the CPU 17 will be described. This embodiment corresponds to the first aspect of the present invention. As described above, since the number of pixels of the CCD image sensor is increasing, display on a liquid crystal display unit requiring high-speed processing and AE / AF control other than when a still image is recorded are performed. In some cases, for example, reading out all pixels takes a long time, so high-speed processing is performed in the skipping reading mode (thinning-out reading mode).

Next, the driving operation in the skip reading mode, which has been conventionally performed, will be described with reference to the timing chart of FIG. 2 and the reading mode explanatory diagram of the CCD image pickup device of FIG. In FIG. 2, VD is a vertical synchronization signal,
The transfer pulse 1 is a pulse for transferring the signal charge of the pixel (photodiode) 101 of the line 1 in the CCD image sensor of FIG. 3 to the vertical register 103, and the transfer pulse 2 is for vertically transferring the signal charge of the pixel 102 of the line 2 Register 103
The pulse is transferred to As shown in FIG. 4, the charge extracting pulse changes the potential V _SUb of the silicon substrate 111 of the CCD image sensor to V _SUb ′ to lower the potential barrier 112 when the element shutter operation is performed, thereby reducing the photodiode constituting the pixel. This pulse is a pulse that discharges all the electric charges 114 stored in the silicon substrate 113 to the silicon substrate 111 and makes the state in which no electric charges are stored in the photodiode 113. In FIG. 4, reference numeral 115 denotes a vertical register;
Indicates the CCD surface.

In FIG. 2, a High level period of the exposure period is a period in which light is incident on the CCD image pickup device and charges are accumulated. When the element shutter is used, the entire period of one screen is not exposed, and a charge extraction pulse is output every predetermined period of one screen. The exposure period is shorter than the entire period of one screen. No charge extraction pulse is output, and the exposure is performed over the entire period of one screen until the signal charge is transferred from the pixel to the vertical register by the transfer pulse.

In the skip read mode, as shown in FIG. 2, the transfer pulse 1 is provided for each vertical synchronization pulse VD (for each screen).
However, the transfer pulse 2 is not output at all, and thus, as shown in FIG. 3, the signal charge is transferred to the vertical register 103 only for the pixel 101 on the line 1, while the signal charge is transferred for the pixel 102 on the line 2. The charge is in the vertical register 103
Not transferred at all. When the transfer pulse 2 is also output for each screen, the all-pixel reading mode is set. In the skipping readout mode, the pixels 10 of only the line 1
1 is transferred to the vertical register 103, and the charges in the vertical register 103 are transferred to the horizontal register 104 by performing two transfer operations for two pixels at a time, and the CCD output from the horizontal register 104 is performed. Is to be obtained.

When such a state is repeated in the driving operation in the skipping read mode, signal charges accumulate in the photodiode of the pixel corresponding to the line 2 in the conventional skip reading mode, as shown in FIG. Since the transfer to the vertical register is not performed, a phenomenon in which the signal charge overflows into the vertical register is likely to occur when the signal charge is accumulated beyond the photodiode capacity.

Therefore, in the present embodiment, as shown in the timing chart of FIG. 6, in the skip reading mode, a charge extracting pulse is always applied at the beginning of one screen. That is, even when the element shutter is not used, a charge extracting pulse is applied at the beginning of one screen, and when exposure is started, all charges in the photodiode are discharged to the substrate as shown in FIG. Exposure is started from a state where no electric charge is accumulated. Therefore, for the pixels on line 2 to which the transfer pulse 2 is not applied and no reading is performed, the charge is discharged to the substrate once per screen, so that the overflow phenomenon to the vertical register occurs. It can be reliably prevented.

Next, a second driving / control mode of the CPU will be described.
An embodiment will be described. This embodiment corresponds to the second aspect of the present invention. In general, in an electronic camera, an operation mode in which a subject image is displayed on a liquid crystal screen using a liquid crystal display unit or the like to adjust the angle of view, and subsequently, a shutter button is pressed to record the subject image as a still image screen on a recording medium. There is an operation mode. When displaying a subject image on the liquid crystal display unit, a skipping readout mode is used in order to perform signal processing at a high speed for display.
On the other hand, when recording a still image on a recording medium, the all-pixel reading mode is used to improve the image quality of the recorded screen.

As described above, in the electronic camera, the still image is recorded on the recording medium by switching from the skipping reading mode to the all-pixel reading mode, and FIG. 6 is a timing chart showing a conventional operation mode of FIG. In FIG. 8, a shutter trigger is a pulse output when a shutter button is pressed. Until the shutter button is pressed, the apparatus operates in the skip reading mode. When the shutter button is pressed and the shutter trigger is output, the mode shifts from the next output VD pulse (vertical synchronization pulse) to the all-pixel reading mode. Then, the recording operation of the still image starts.

In the skipping read mode, as described in the first embodiment, only the transfer pulse 1 is set to 1
The output is at the beginning of the screen, and no transfer pulse 2 is output. Note that, at this time, the element shutter operation is not used, and thus no charge extraction pulse is output. When the shutter trigger is output and the mode shifts from the skip reading mode to the all-pixel reading mode, the first 1 VD of the all-pixel reading mode is set.
In the period, the exposure mode is set in which light is incident on the CCD image pickup device and charges are accumulated. Then, the charges accumulated during the exposure mode are read out during the next readout mode. Here, when shifting from the exposure mode for the all-pixel reading mode to the reading mode, both the transfer pulses 1 and 2 are applied to read all the pixels.

FIG. 9 is a diagram showing a read operation mode of the CCD image pickup device at the timing A in the timing chart of FIG. 8, that is, at the time of transition from the skip read mode to the exposure mode of the all-pixel read mode.
In the skipping readout mode, charge transfer from the photodiode to the vertical register 103 is not performed for the pixel 102 on line 2; therefore, charge transfer is performed only for the pixel 101 on line 1, and the pixel 102 on line 2 is not transferred. The charge remains in the photodiode. At timing B in FIG. 8, that is, at the time of transition from the exposure mode to the read mode in the all-pixel read mode, all the pixels are read out.
As shown in FIG. 10, transfer pulses 1 and 2 are output together, and for lines 1 and 2, charge transfer to the vertical register 103 is performed as shown in FIG. However, at this time, with respect to the pixel 102 on the line 2, in the skip read mode in which the element shutter operation is not used, the charge is not read out or the charge is not drawn out, so that the charge subjected to the multiple exposure is supplied to the photodiode. When the charge is transferred in line 1 and line 2 due to the accumulation, signal charges having different exposure times are output.

Therefore, in the present embodiment, a shutter trigger is output as shown in the timing chart of FIG. 11, and when shifting from the skip reading mode to the all-pixel reading mode, the shutter trigger is completely output in the skip reading mode. The remaining charge extraction pulse is output at least once immediately after switching to the all-pixel reading mode. As a result, all the charges accumulated in the photodiodes of all the pixels are once swept out, so that in the exposure mode in the all-pixel reading mode, the exposure is started with no charges accumulated, and the accumulation of the charges is started. Begin. Therefore, during the readout period in the all-pixel readout mode, the transfer pulses 1 and 2 are both output, and the signal charges having different exposure levels as shown in FIG. Does not occur, and a still image is recorded even when the shutter speed is changed.

Next, a third embodiment of the mode of driving and controlling the CPU will be described with reference to FIG. This embodiment corresponds to the third aspect of the present invention, and similarly to the second embodiment shown in FIG. 11, at the time of transition from the skip reading mode to the all-pixel reading mode, exposure of each line is performed. In this embodiment, the charge extraction pulse is output immediately after switching to the all-pixel readout mode, as in the second embodiment shown in FIG. Is not configured, the shutter trigger is output, the mode shifts to the all-pixel readout mode, and immediately before the exposure mode in the all-pixels readout mode starts, the transport pulse 2 is output together with the transport pulse 1 to skip the readout mode during the exposure mode period. By performing the transfer in the same manner as in the operation at the time, all the charges in the photodiodes of all the pixels are transferred to the vertical register and then to the horizontal register. Therefore, the accumulated charges in all the photodiodes and the vertical registers become empty. The signal charges exposed and accumulated during the exposure mode are transferred from all the photodiodes to the vertical register by outputting both the transfer pulse 1 and the transfer pulse 2 again at the beginning of the read mode, thereby reading all the pixels. Is performed.

In the second and third embodiments shown in FIGS. 11 and 12, the reading mode of the CCD image pickup device at the timing B, that is, at the beginning of the reading mode, is shown in FIG. The read mode of the CCD image sensor at the timing B when the read mode starts in the conventional example shown in FIG. 8 is shown in FIG. 10, but in this read mode, in line 1 and line 2, line 2 is subjected to multiple exposure and both lines are exposed. Although the exposure time was different, the second
And in the third embodiment, as shown in FIG.
At the beginning of the exposure mode, all the photodiodes have no accumulated charge at all, so the accumulated charge in the same exposure period regardless of the line is equal to the first timing B of the read mode.
Is read out. As described above, in the second and third embodiments shown in FIGS. 11 and 12, when the mode is shifted from the skip reading mode to the all-pixel reading mode,
The accumulated charges in the same exposure period can be read regardless of the line.

Next, a fourth embodiment of the drive / control mode of the CPU will be described with reference to the timing chart of FIG. This embodiment corresponds to the invention described in claim 4. As in the third embodiment shown in FIG.
When shifting from the skipping readout mode to the all-pixels readout mode, when both the transfer pulse 1 and the transfer pulse 2 are output to read out the signal charges of all the pixels, the signal charges from all the photodiodes to the vertical register are transferred. The accumulated charges in all the photodiodes are emptied, but the charges transferred from the photodiodes remain in the vertical registers at the time of the transfer to the vertical registers.
However, the transferred electric charge in the vertical register is an unnecessary electric charge. In particular, the electric charge transferred from the photodiode of the pixel in line 2 is an unnecessary electric charge because it is based on the multiple exposure. Therefore, all the charges transferred into the vertical register are once output to the outside during the exposure mode.

Therefore, in the present embodiment, when the signal charges from the photodiodes of all the pixels are transferred to the vertical register as in the third embodiment shown in FIG.
As shown in FIG. 14, the configuration is such that unnecessary charges in the vertical register are transferred at high speed during the exposure mode, and all charges are discharged. As described above, by performing high-speed transfer and repeatedly sweeping out and outputting unnecessary charges, smear components leaking into the register can be removed at the same time.

Next, a fifth embodiment will be described. This embodiment corresponds to the invention described in claim 5. In general, when a moving image is output using an element shutter in an electronic camera, one screen is created for each VD (vertical synchronization signal) shown in FIG. 15. The stored signal charges are transferred to the vertical register, and the video data is displayed within the period of the next one screen. Here, when the element shutter operation is used, as shown in FIG. 15, the charge extraction pulse is always supplied from the beginning of one screen to the exposure start time for setting the exposure period necessary for the element shutter operation. Output, when the exposure start time to make the required exposure period has arrived, stop outputting the charge extraction pulse, the period from the exposure start time until the next transfer pulse is output becomes the exposure period, Electric charges are accumulated in the photodiode during this exposure period.

However, since the voltage of the charge extracting pulse used to perform the element shutter operation is high and a large number of charge extracting pulses are output, a large amount of power is consumed as shown in FIG. Reduce battery life.

Therefore, in the present embodiment, as shown in FIG. 16, a large number of charge extraction pulses are not output, and the number of charge extraction pulses is reduced to a minimum number. Here, when the element shutter operation is used, only the exposure period from when the charge extraction pulse is not output until the transfer pulse is output is important, and therefore, the period before the exposure period is created. Need not output a charge extraction pulse over the entire period. In other words, immediately before the exposure start time for making the exposure period has arrived, the charge extraction pulse is output at least once to discharge the electric charge, so that the next transfer from the time when the electric charge is discharged is performed. A period until a pulse is output is an exposure period, and charges based on a predetermined shutter operation are accumulated in the photodiode.

As described above, it is sufficient that the charge extraction pulse is output at least once immediately before the exposure start time, instead of being output over the entire period from the beginning of one screen to immediately before the exposure start time. become. FIG. 16 shows a case in which the charge extraction pulse is output three times. However, the output of the charge extraction pulse is performed twice or more. Even in this case, the remaining charges can be discharged by the further output pulse, so that accurate exposure and accumulated charges based on the element shutter operation can be obtained while reducing power consumption.

Next, a sixth embodiment will be described. This embodiment corresponds to the invention described in claim 6. Generally, in an electronic camera, an operation is performed in which a moving image is displayed on a monitor connected via a liquid crystal display or a cable until a shutter button is pressed, and a still image is recorded on a recording medium when the shutter button is pressed. Will be FIG. 17 is a timing chart for explaining operations in a conventional moving image output mode for outputting a moving image and a still image recording mode for recording a still image. As shown in FIG. 17, when the shutter button is pressed and a shutter trigger is output, the mode shifts from the moving image output mode to the still image recording mode.
The period of the still image recording mode is, first, the period of the exposure mode in which light is exposed to the CCD image pickup device and the period of the read mode for reading out the electric charges accumulated during the exposed period and recording as a still image. Become. In the reading mode period in the still image recording mode, the charges exposed in the previous exposure mode period are read out. However, when the reading mode period ends, a still image is recorded and the process returns to the next moving image output mode. Conventionally, as shown in FIG. 17, an exposure period is provided even in the period of the read mode, and charges from the exposure in the period of the moving image output mode are read from the next screen.

However, when the method of providing the exposure period within the period of the read mode is used, the method shown in FIG.
As shown in (1), since the charge extraction pulse is not output during the exposure period, a period during which the charge extraction pulse is output and a period during which the charge extraction pulse is not output occur during the read mode. Since the voltage of the charge extraction pulse is high, the power supply voltage greatly fluctuates at the boundary between the period during which the charge extraction pulse is output and the period during which the charge extraction pulse is not output, and the boundary is caused by noise or the like. A horizontal streak 122 occurs in the output of the still image screen 121 at the timing of the portion.

Therefore, in the present embodiment, in order to prevent the occurrence of horizontal streaks on the still picture screen, as shown in FIG. The configuration is such that a charge extraction pulse is output to eliminate the exposure period and inhibit the accumulation of charges in the photodiode. With this configuration, as shown in FIG. 19B, two states of a period during which the charge extraction pulse is output and a period during which the charge extraction pulse is not output occur during the read mode, and all the states are not generated. Since the charge extraction pulse is output over the reading period, no horizontal streak occurs on the still image screen, and no voltage fluctuation occurs. In addition, since the charge extraction pulse is always output during the readout period, unnecessary charges may overflow from the photodiode into the charge transfer path even if abnormally strong light partially enters the photodiode. Absent. Note that, in this embodiment, a charge extraction pulse is output over the entire period of the read mode in the still image recording mode to expose and accumulate the charges to be read in the next moving image output mode following the still image recording mode. Since no exposure period is provided, the first screen of the next moving image output mode following the still image recording mode is not output. However, immediately after the end of the readout period in the still image recording mode, the recording operation processing on the recording medium is performed, and the next photographing operation is not performed immediately. There is no.

[0042]

As described above with reference to the embodiment, according to the first aspect of the present invention, the operation of extracting the signal charge from the pixel at the time of driving in the thinning-out reading mode is performed by one.
Since the operation is performed once or more in each screen readout period, it is possible to prevent overflow of signal charges generated during the driving in the thinning-out readout mode, thereby eliminating the need to perform interlace scanning and generating flicker. The advantage of not doing so is obtained. According to the second aspect of the present invention, when shifting from the thinning-out readout mode to the all-pixel readout mode, the signal charge is extracted one or more times immediately before the start of exposure in the all-pixel readout mode. In addition, signal charges due to multiple exposure in the thinning-out reading mode are discharged and can be prevented from being mixed in when reading out all pixels. According to the third aspect of the invention, when shifting from the thinning-out readout mode to the all-pixels readout mode, signal charges are transferred from all the pixels to the vertical register at the beginning of the one-screen readout period immediately before the pixel signals of all the pixels are read out. , So that all pixels can start exposure from an empty state, and prevent signal charges due to multiple exposure in the thinning-out readout mode from being mixed in when reading out all the pixels. be able to. According to the fourth aspect of the present invention, when shifting from the thinning-out reading mode to the all-pixel reading mode, the signal charges are transferred from all the pixels to the vertical register immediately before the pixel signals of all the pixels are read, and then the vertical charge is transferred. Since the signal charge in the register is configured to be transferred at high speed, all pixels can start exposure from the state where the charge is empty, and the signal charge due to multiple exposure in the thinning-out reading mode is mixed in when reading out all pixels And the smear component leaking into the vertical register can be removed at the same time. According to the fifth aspect of the present invention, since the operation of extracting the signal charge from the pixel for providing the element shutter function is performed n times immediately before the start of the exposure, the exposure is started while reducing the power consumption. The previous signal charges can be reliably discharged. According to the sixth aspect of the invention, in the readout period when the output of the image sensor is used as a still image, the operation of extracting the signal charges from the pixels is repeated to prohibit the exposure operation. It is possible to prevent the occurrence of horizontal streaks based on noise generated at the time of switching of the charge extracting operation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration in which an imaging apparatus according to the present invention is applied to an electronic camera.

FIG. 2 is a timing chart for explaining a driving operation in a conventional skip read mode.

FIG. 3 is an explanatory diagram showing a reading mode of a CCD image pickup device in a conventional skip reading mode.

FIG. 4 is an explanatory diagram for explaining an element shutter operation in the CCD image sensor.

FIG. 5 is an explanatory diagram showing an overflow state of accumulated charges due to multiple exposure in a conventional skip reading mode.

FIG. 6 is a timing chart for explaining a first embodiment of a driving / control mode by a CPU in the electronic camera shown in FIG. 1;

FIG. 7 is an explanatory diagram showing an accumulation state of signal charges of the CCD image sensor at the time of driving / control shown in FIG. 6;

FIG. 8 is a timing chart for explaining a driving operation at the time of transition from the conventional skip reading mode to the all-pixel reading mode.

9 is an explanatory diagram illustrating an operation mode of the CCD imaging device at a timing A in the timing chart illustrated in FIG. 8;

10 is an explanatory diagram illustrating an operation mode of the CCD imaging device at a timing B in the timing chart illustrated in FIG. 8;

11 is a timing chart for explaining a second embodiment of a driving / control mode by the CPU in the electronic camera shown in FIG. 1.

12 is a timing chart for explaining a third embodiment of a driving / control mode by the CPU in the electronic camera shown in FIG. 1.

13 is an explanatory diagram illustrating an operation mode of the CCD imaging device at a timing B in the timing charts illustrated in FIGS. 11 and 12. FIG.

FIG. 14 is a timing chart for explaining a fourth embodiment of a driving / control mode by the CPU in the electronic camera shown in FIG. 1.

FIG. 15 is a timing chart for describing a driving operation when a moving image is output using an element shutter in a conventional imaging apparatus.

16 is a timing chart for explaining a fifth embodiment of a driving / control mode by the CPU in the electronic camera shown in FIG. 1.

FIG. 17 is a timing chart for explaining operations in a moving image output mode and a still image recording mode in a conventional imaging device.

18 is a timing chart for explaining a sixth embodiment of the driving / control mode by the CPU in the electronic camera shown in FIG. 1.

FIG. 19 is a diagram showing a form of a still image screen formed by an operation based on the timing charts shown in FIGS. 17 and 18.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CCD image sensor 2 Aperture 3 Correlated double sampling circuit 4 Amplifier 5 A / D converter 6 Process circuit 7 DRAM 8 Compression / expansion circuit 9 Recording medium 10 AF circuit 11 AE circuit 12 Auto white balance circuit 13 Liquid crystal display part 14 Interface circuit 15 Timing Generator 16 SG Circuit 17 CPU 101 Line 1 Pixel 102 Line 2 Pixel 103 Vertical Register 104 Horizontal Register 111 Silicon Substrate 112 Potential Barrier 113 Photodiode 114 Accumulated Charge 115 Vertical Register 116 CCD Surface 121 Still Image Screen 122 Horizontal Line

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[Procedure amendment]

[Submission date] September 22, 1998

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

[Correction method] Change

[Correction contents]

FIG. 6

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yoshitaka Ogawa 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (6)

[Claims] 1. A pixel comprising a plurality of photoelectric conversion elements arranged two-dimensionally in a horizontal direction and a vertical direction, a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction, and a signal of the vertical register. In a solid-state imaging device having a horizontal register that transfers electric charges in the horizontal direction, and an imaging device including a control unit that drives and controls the solid-state imaging device, the control unit is configured to control all pixels of the solid-state imaging device. A driving function in an all-pixel reading mode in which a signal charge is transferred to a vertical register and a pixel signal is read out, and a vertical m
(M is a positive integer of 2 or more) A driving function of a thinning-out reading mode for transferring a signal charge from n (n is a positive integer of 1 or more) pixels to a vertical register and reading out pixel signals for each pixel And a device shutter function for extracting a signal charge from the pixel and controlling the photoelectric conversion time of the pixel. In the thinning-out reading mode, the operation for extracting the signal charge from the pixel is performed once every one reading period of one screen. An imaging apparatus characterized in that the imaging is performed more than once. 2. A pixel comprising a plurality of photoelectric conversion elements two-dimensionally arranged in a horizontal direction and a vertical direction, a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction, and a signal of the vertical register. In a solid-state imaging device having a horizontal register that transfers electric charges in the horizontal direction, and an imaging device including a control unit that drives and controls the solid-state imaging device, the control unit is configured to control all pixels of the solid-state imaging device. A driving function in an all-pixel reading mode in which a signal charge is transferred to a vertical register and a pixel signal is read out, and a vertical m
(M is a positive integer of 2 or more) A driving function of a thinning-out reading mode for transferring a signal charge from n (n is a positive integer of 1 or more) pixels to a vertical register and reading out pixel signals for each pixel And has an element shutter function of extracting a signal charge from the pixel and controlling a photoelectric conversion time of the pixel. Immediately after the thinning-out readout mode drive, when performing the all-pixel readout mode drive, the pixel immediately before the start of exposure. An image pickup device configured to perform an operation of extracting signal charges from a device at least once. 3. A pixel comprising a plurality of photoelectric conversion elements arranged two-dimensionally in a horizontal direction and a vertical direction, a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction, and a signal of the vertical register. In a solid-state imaging device having a horizontal register that transfers electric charges in the horizontal direction, and an imaging device including a control unit that drives and controls the solid-state imaging device, the control unit is configured to control all pixels of the solid-state imaging device. A driving function in an all-pixel reading mode in which a signal charge is transferred to a vertical register and a pixel signal is read out, and a vertical m
(M is a positive integer of 2 or more) A driving function of a thinning-out reading mode for transferring a signal charge from n (n is a positive integer of 1 or more) pixels to a vertical register and reading out pixel signals for each pixel And has an element shutter function of extracting a signal charge from the pixel and controlling a photoelectric conversion time of the pixel, and immediately after the driving in the thinning-out reading mode, when performing the driving in the all-pixel reading mode, the pixel signals of all the pixels are An imaging apparatus characterized in that signal charges are transferred from all pixels to the vertical register at the beginning of a reading period of one screen immediately before reading. 4. A pixel comprising a plurality of photoelectric conversion elements arranged two-dimensionally in a horizontal direction and a vertical direction, a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction, and a signal of the vertical register. In a solid-state imaging device having a horizontal register that transfers electric charges in the horizontal direction, and an imaging device including a control unit that drives and controls the solid-state imaging device, the control unit is configured to control all pixels of the solid-state imaging device. A driving function in an all-pixel reading mode in which a signal charge is transferred to a vertical register and a pixel signal is read out, and a vertical m
(M is a positive integer of 2 or more) A driving function of a thinning-out reading mode for transferring a signal charge from n (n is a positive integer of 1 or more) pixels to a vertical register and reading out pixel signals for each pixel And has an element shutter function of extracting a signal charge from the pixel and controlling a photoelectric conversion time of the pixel, and immediately after the driving in the thinning-out reading mode, when performing the driving in the all-pixel reading mode, the pixel signals of all the pixels are Immediately before reading, an image pickup apparatus is configured to transfer signal charges from all pixels to the vertical register, and then transfer the signal charges in the vertical register at a high speed. 5. A pixel comprising a plurality of photoelectric conversion elements arranged two-dimensionally in a horizontal direction and a vertical direction, a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction, and a signal of the vertical register. An image pickup apparatus comprising: a solid-state imaging device having a horizontal register for transferring charges in a horizontal direction; and control means for driving and controlling the solid-state imaging device, wherein the control means extracts signal charges from the pixels and performs photoelectric conversion. An element shutter function for controlling time is provided, and the operation of extracting signal charges from the pixel is performed n times (n is a positive integer of 1 or more) immediately before the start of exposure. Imaging device. 6. A pixel comprising a plurality of two-dimensionally arranged photoelectric conversion elements arranged in a horizontal direction and a vertical direction, a vertical register for receiving a signal charge of each pixel and transferring the signal charge in a vertical direction, and a signal of the vertical register. An image pickup apparatus comprising: a solid-state imaging device having a horizontal register for transferring charges in a horizontal direction; and control means for driving and controlling the solid-state imaging device, wherein the control means extracts signal charges from the pixels and performs photoelectric conversion. In a readout period using an output of the solid-state imaging device as a moving image output, the operation of extracting signal charges from the pixels includes a device shutter function for controlling time,
Immediately before the start of exposure, n (n is a positive integer equal to or greater than 1) times, and during a readout period using the output of the solid-state imaging device as a still image, the operation of extracting signal charges from the pixels is repeated to inhibit the exposure operation. An imaging apparatus characterized in that it is configured to perform